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Blame SOURCES/kvm-block-Switch-BdrvTrackedRequest-to-byte-granularity.patch

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From e0f594c3eac9fb0a89c76de3b77bce03c235b36e Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Tue, 3 Dec 2013 15:31:25 +0100
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Subject: [PATCH 16/37] block: Switch BdrvTrackedRequest to byte granularity
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Message-id: <1392117622-28812-17-git-send-email-kwolf@redhat.com>
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Patchwork-id: 57181
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O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 16/37] block: Switch BdrvTrackedRequest to byte granularity
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Bugzilla: 748906
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Reviewed-by: Benoit Canet <benoit@irqsave.net>
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(cherry picked from commit 793ed47a7a2b09b67cb2a8863dff531436532b5c)
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Conflicts:
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	block/backup.c
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	include/block/block_int.h
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Conflicts because in RHEL 7...
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- ...block-backup doesn't exist
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- ...BdrvTrackedRequest is in block.c rather than block_int.h
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 block.c | 56 ++++++++++++++++++++++++++++++++++++--------------------
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 1 file changed, 36 insertions(+), 20 deletions(-)
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---
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 block.c |   56 ++++++++++++++++++++++++++++++++++++--------------------
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 1 files changed, 36 insertions(+), 20 deletions(-)
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diff --git a/block.c b/block.c
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index 7b8131c..09bb127 100644
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--- a/block.c
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+++ b/block.c
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@@ -2036,8 +2036,8 @@ int bdrv_commit_all(void)
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 struct BdrvTrackedRequest {
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     BlockDriverState *bs;
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-    int64_t sector_num;
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-    int nb_sectors;
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+    int64_t offset;
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+    unsigned int bytes;
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     bool is_write;
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     QLIST_ENTRY(BdrvTrackedRequest) list;
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     Coroutine *co; /* owner, used for deadlock detection */
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@@ -2060,13 +2060,13 @@ static void tracked_request_end(BdrvTrackedRequest *req)
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  */
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 static void tracked_request_begin(BdrvTrackedRequest *req,
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                                   BlockDriverState *bs,
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-                                  int64_t sector_num,
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-                                  int nb_sectors, bool is_write)
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+                                  int64_t offset,
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+                                  unsigned int bytes, bool is_write)
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 {
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     *req = (BdrvTrackedRequest){
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         .bs = bs,
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-        .sector_num = sector_num,
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-        .nb_sectors = nb_sectors,
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+        .offset = offset,
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+        .bytes = bytes,
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         .is_write = is_write,
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         .co = qemu_coroutine_self(),
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     };
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@@ -2097,25 +2097,43 @@ void bdrv_round_to_clusters(BlockDriverState *bs,
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     }
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 }
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+static void round_bytes_to_clusters(BlockDriverState *bs,
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+                                    int64_t offset, unsigned int bytes,
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+                                    int64_t *cluster_offset,
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+                                    unsigned int *cluster_bytes)
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+{
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+    BlockDriverInfo bdi;
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+
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+    if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
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+        *cluster_offset = offset;
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+        *cluster_bytes = bytes;
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+    } else {
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+        *cluster_offset = QEMU_ALIGN_DOWN(offset, bdi.cluster_size);
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+        *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes,
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+                                       bdi.cluster_size);
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+    }
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+}
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+
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 static bool tracked_request_overlaps(BdrvTrackedRequest *req,
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-                                     int64_t sector_num, int nb_sectors) {
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+                                     int64_t offset, unsigned int bytes)
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+{
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     /*        aaaa   bbbb */
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-    if (sector_num >= req->sector_num + req->nb_sectors) {
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+    if (offset >= req->offset + req->bytes) {
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         return false;
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     }
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     /* bbbb   aaaa        */
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-    if (req->sector_num >= sector_num + nb_sectors) {
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+    if (req->offset >= offset + bytes) {
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         return false;
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     }
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     return true;
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 }
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 static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
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-        int64_t sector_num, int nb_sectors)
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+        int64_t offset, unsigned int bytes)
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 {
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     BdrvTrackedRequest *req;
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-    int64_t cluster_sector_num;
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-    int cluster_nb_sectors;
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+    int64_t cluster_offset;
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+    unsigned int cluster_bytes;
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     bool retry;
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     /* If we touch the same cluster it counts as an overlap.  This guarantees
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@@ -2124,14 +2142,12 @@ static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
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      * CoR read and write operations are atomic and guest writes cannot
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      * interleave between them.
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      */
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-    bdrv_round_to_clusters(bs, sector_num, nb_sectors,
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-                           &cluster_sector_num, &cluster_nb_sectors);
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+    round_bytes_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes);
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     do {
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         retry = false;
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         QLIST_FOREACH(req, &bs->tracked_requests, list) {
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-            if (tracked_request_overlaps(req, cluster_sector_num,
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-                                         cluster_nb_sectors)) {
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+            if (tracked_request_overlaps(req, cluster_offset, cluster_bytes)) {
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                 /* Hitting this means there was a reentrant request, for
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                  * example, a block driver issuing nested requests.  This must
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                  * never happen since it means deadlock.
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@@ -2746,10 +2762,10 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
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     }
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     if (bs->copy_on_read_in_flight) {
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-        wait_for_overlapping_requests(bs, sector_num, nb_sectors);
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+        wait_for_overlapping_requests(bs, offset, bytes);
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     }
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-    tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
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+    tracked_request_begin(&req, bs, offset, bytes, false);
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     if (flags & BDRV_REQ_COPY_ON_READ) {
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         int pnum;
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@@ -2998,10 +3014,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
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     assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
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     if (bs->copy_on_read_in_flight) {
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-        wait_for_overlapping_requests(bs, sector_num, nb_sectors);
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+        wait_for_overlapping_requests(bs, offset, bytes);
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     }
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-    tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
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+    tracked_request_begin(&req, bs, offset, bytes, true);
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     if (flags & BDRV_REQ_ZERO_WRITE) {
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         ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
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-- 
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1.7.1
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